The present invention relates to metallurgical apparatus and more particularly to cooling plates for insertion into the refractory lining of a blast furnace or the like.
Cooling systems are provided for the furnace walls of shaft furnaces as e.g. blast furnaces to effectively cool the walls subjected to high temperature conditions. The cooling systems comprise a plurality of cooling plates inserted in a pattern developed to adequately cool the furnace walls so that failure or breakout is prevented.
The cooling plates with circulating water are used in the bosh, belly and stack sections of a blast furnace to cool the refractory lining in order to stabilize and extend the life of refractories. The plates are generally inserted horizontally and imbedded in the refractory lining at desired spacing both in circumferential and vertical directions. The cooling plates are usually made of copper castings with essentially pure copper for high thermal conductivity.
The cooling plates are subject to failure by burnout or cracking due to two main factors. One factor is insufficient water flow, resulting in insufficient heat transfer. The other and more important factor is the existence of stagnant zones inside the cooling plates, such as dead pockets, eddies or vortices. The stagnation of water causes film boiling on the surface of the copper plate, leading to melting and burnout. The failures not only necessitate purchase of a large quantity of expensive replacement plates, but also cause the shutdown of the furnace and consequent loss of production from that unit.
Many designs of cooling plates have been made to overcome the deficiencies noted above but the search continues for a more effective design.